The protease-activated receptor 1 (PAR1) is a thrombin receptor which belongs to the class of G protein-coupled receptors (GCPR). The gene for PAR1 is located on chromosome 5q13, consists of two exons and covers a region of approx. 27 kb. PAR1 is expressed in, inter alia, endothelial cells, smooth muscles cells, fibroblasts, neurons and human platelets. In platelets, PAR1 is an important signal transduction receptor which is involved in the initiation of platelet aggregation.
PARs are activated via proteolytic removal of a part of the N terminus of said PARs, whereby a new N-terminal sequence is exposed which then activates the receptor.
PAR1 and PAR4 play a central part in the activation of platelets; the activation of these receptors in platelets leads to morphological changes, release of ADP and aggregation of said platelets.
A connection of coronary heart diseases with single nucleotide polymorphisms (SNP) in the promoter region of PAR1 in a group of Korean patients was not confirmed. In another study, a PAR1 promoter variant was shown to have a protective action for the development of venous thromboembolisms.
The sequence of the human PAR1 gene is known. The polynucleotide sequence of this gene can be accessed under the number NM-001992 at the NCBI nucleotide database. Likewise, the protein sequence is available under the number NP-001983 at the NCBI protein database. NCBI is the National Center for Biotechnology Information (postal address: National Center for Biotechnology Information, National Library of Medicine, Building 38A, Bethesda, Md. 20894, USA; Web address: www.ncbi.nhm.nih.gov). The cloning of the PAR1 gene has been described, inter alia, in “Schmidt et al., J. Biol. Chem. 271, 9307-9312, 1996”.